Tag: cosmology

Sometimes, distractions can be useful in themselves. That’s the message this week from the Planck space telescope, which has a mighty big mission: to take baby pictures of the universe. While it hasn’t yet accomplished that task, the preliminary disturbances that Planck scientists are now dealing with are yielding cosmic insights of their own.

Orbiting the Sun roughly 1.5 million kilometres from Earth, the Planck space-based telescope is scanning the sky for ultra-cold objects. Its instruments are chilled to just a tenth of a degree above absolute zero and are designed to pick up the faint microwave afterglow from the Big Bang, which scientists hope can tell them about the earliest moments of the Universe. [Nature News]

Planck was launched in spring of 2009 by the European Space Agency, and it’s still gathering data to complete its chart of this cosmic microwave background (CMB); researchers hope the map will shed light on the young universe’s brief “inflationary” period when it expanded extremely rapidly. At the moment, however, Planck is busy detecting other sources of microwaves so that it can subtract this “foreground” radiation from its map of the background.

More than a trillion pixels from a million-plus images, combined to create the most detailed map of the universe ever created—one that would require a wall of a half-million HDTVs to properly appreciate. Not bad for something that looks a little like tan carpeting.

What you’re seeing is about one-third of the sky, imaged by the Sloan Digital Sky Survey, which has been assembling images from Apache Point Observatory in New Mexico for more than a dozen years to image the cosmos in unprecedented detail.

It replaces an image that is now over half a century old, created on photographic plates by the Palomar Sky Survey in the 1950s but still used by astronomers today. It contains 10 times as many objects – such as galaxies, stars and nebulae – as the Palomar survey and scientists hope it will be used for decades to come by astronomers hunting for everything from dark matter to planets orbiting other stars. [The Guardian]

The eminent Oxford physicist has long advocated the wild idea of “conformal cyclic cosmology,” a cyclical universe without beginning or end in which the Big Bang 13.75 billion years ago was simply one of many. This month, Penrose pushed his idea further: His team says it has detected a pattern in the cosmic microwave background—radiation left over from just after the Big Bang—that represents the echo of events that occurred before the Big Bang itself.

Penrose examined the data from the Wilkinson Microwave Anisotropy Probe (WMAP), the mission that just completed nine years of surveying the cosmic microwave background across the sky. His study points to concentric circular patterns in the WMAP data where he says he found something surprising:

The circular features are regions where tiny temperature variations in the otherwise uniform microwave background are smaller than average. Those features, Penrose said, cannot be explained by the highly successful inflation theory, which posits that the infant cosmos underwent an enormous growth spurt, ballooning from something on the scale of an atom to the size of a grapefruit during the universe’s first tiny fraction of a second. Inflation would either erase such patterns or could not easily generate them. [Science News]

To get a better handle on these “dark” forces, which we can’t detect with our puny human equipment, researchers Christian Marinoni and graduate student Adeline Buzzi from the University of Provence used an approach that’s actually been around longer than the idea of dark energy–a 1979 theory from Charles Alcock.

The record for the most distant object in the Universe ever seen has been smashed: a galaxy has been found at the staggering distance of 13.1 billion light years!

…

It’s so dim that the faintest star you can see with your unaided eye is 4 billion times brighter. Its distance is simply numbing; the Universe itself is only 13.7 billion years old, so the light from this object began its journey on its way to Earth just 600 million years after the Universe itself formed.

Head to the full post at Bad Astronomy for all the details about how astronomers used the Hubble Space Telescope to find this faraway galaxy, and what the discovery tells us about the infant universe.

After analyzing light coming from distant quasars, some researchers have asked a physical constant a blunt question: Are you really constant at all? And since the “fine structure constant” that they’re interrogating is important for how physicists understand things like electrons’ behavior in atoms and fusion in stars, other physicists are asking their own question: Are your measurements correct?

The paper, which appeared last month in arXiv, argues that the constant might vary depending on location. This controversial claim is a new twist on a previous controversial claim–made over the past decade by some of the same physicists–which said that the constant varied with time.

Craig Hogan of the University of Chicago and the Fermi National Accelerator Laboratory in Batavia, Ill., acknowledges that “it’s a competent team and a thorough analysis.” But because the work has such profound implications for physics and requires such a high level of precision measurements, “it needs more proof before we’ll believe it.” [Science News]

Last month the renowned physicists made the news by warning of the great threat of human extinction over the next couple centuries, but kindly softened the blow by saying that we’ll be fine if we can get through our growing pains and get off this planet. Back in April, the wave of attention came from his warning that it might not be such a great idea to attempt to contact aliens, should they be more advanced than us and try to wipe us out.

Now, he’s taking on the almighty. Hawking’s new book, The Grand Design, co-authored by Leonard Mlodinow, snagged media attention this week because of an excerpt that appeared in the U.K.’s The Times (which we can’t link to, because it’s behind an online pay wall).

“Spontaneous creation is the reason why there is something rather than nothing, why the universe exists, why we exist,” he wrote. “It is not necessary to invoke God to light the blue touch paper [fuse] and set the universe going.” [CNN]

Or, to put it another way, here’s a bit from the book’s final chapter about the nature of the universe:

One of the top three priorities for the next decade of astrophysics and astronomy, we noted this week, is unraveling dark energy, the weird force that pushes the universe apart. Given that scientists know next-to-nothing about dark energy—besides the fact that it makes up most of the universe—any step could be an important one. Thanks to a study out this week in Science, astrophysicists at least can have more confidence in this phenomenon that can’t be directly seen or measured: Their estimates for dark matter’s extent appear to be on target.

The technique scientists used in this study is called gravitational lensing, and the lens in this case is a huge galactic cluster called Abell 1689.

Because of its huge mass, the cluster acts as a cosmic magnifying glass, causing light to bend around it. The way in which light is distorted by this cosmic lens depends on three factors: how far away the distant object is; the mass of Abell 1689; and the distribution of dark energy [BBC News].

There is a lot of space to explore and a limited amount of money to spend. So every ten years the National Research Council’s “Decadal Survey” recommends which astronomy and astrophysics projects should get first dibs. Last week, the committee released their recommendations for 2012 through 2021. The projects that got the thumbs-up from astronomers would tackle big tasks, like hunting for dark energy and seeking out new exoplanets.

Though funding agencies (like NASA, the National Science Foundation, and the Department of Energy), Congressional committees, and the scientific community often use the survey to select the observatories on which to focus attention and resources, some were skeptical about this report given the 2001 survey’s recommendations and results.

Although these reports have always been influential—policymakers like scientists to rank their needs—only two of the seven major projects that appeared on the wish list in the 2001 survey have been funded, leading astronomers to wonder if the exercise is as useful as they’d like it to be. Previous surveys have also been faulted for providing unrealistic cost estimates, as low as a fifth of what certain missions have ended up costing. As a result, there has been considerable pressure on the committee that authored [Friday’s] report to prioritize projects more effectively and estimate costs better. [Science Insider]

Detectors buried thousands of feet under the Antarctic ice recently confirmed a mysterious cosmic lopsidedness. Though it might seem reasonable for our planet to receive energetic particles, called cosmic rays, on average from all directions equally, more cosmic rays’ seem to approach Earth from certain preferred directions.

The IceCube Neutrino Observatory, which is still under construction, confirmed these odd cosmic ray preferences, previously detected in the northern hemisphere.

Cosmic rays–energetic particles flung from as nearby as the sun and light years away–are the extra “noise” in the observatory’s experiments; to filter out this noise, researchers needed to map where the cosmic rays are coming from. In a paper published earlier this month in The Astrophysical Journal they confirmed that more cosmic rays seem to come from certain directions–an observation known as anisotropy–in the Earth’s southern hemisphere too.

[T]hey used IceCube to study a longstanding puzzle: whether the distribution of cosmic ray arrivals is uneven across the southern sky, as scientists have previously observed in the northern hemisphere. Indeed, the team found, IceCube detected a disproportionate number of cosmic rays arriving from some parts of the sky. But the reason for this uneven distribution remains unclear. [ScienceNOW]